Wireless communication systems are today well known in the art having fundamentally changed how consumers, advertisers, and enterprises interact, communicate, exchange, store, and utilize information through a variety of formats including text, electronic mail, video, multimedia, and plain-old-telephone-service (POTS) as well as through a variety of mobile wireless devices from cellular telephones (cellphones), personal digital assistants (PDAs), laptops, tablet PCs, portable multimedia players, and portable gaming consoles. The Technology, Media and Telecommunications (TMT) business has grown in the past 10 years with the widespread deployment of wireless devices, personal computers, Internet, and broadband networks to represent a value chain of over $3 trillion worldwide, including content providers, advertisers, telecommunications companies and electronics suppliers (White Paper Wireless Social Networking from iSuppli, July 2008).
In the next decade wireless social networking products alone (applications, components, and advertising) will generate more than $2.5 trillion in revenue by 2020, according to iSuppli (Press Release, Jun. 4, 2008 http://www.isuppli.com/NewsDetail.aspx?ID=12930). During this timeframe it is anticipated that mobile devices, such as cellular telephones, smart phones, personal digital assistants (PDA), will become the primary channel for viewing content from or accessing the Internet (World Wide Web) and that many applications such as social networking, email, and financial transactions will have moved substantially into the wireless realm providing the degree and type of ubiquitous connection that consumers demand. At the same time it is anticipated that this evolution will be accompanied by the creation of a new generation of applications that will greatly expand the appeal, utility, and capabilities of mobile wireless devices.
Today, with a global population of approximately 6.9 billion there are estimated to be 5 billion active cellphone connections globally (see BBC Jul. 18, 2010 new report http://www.bbc.co.uk/news/10569081 citing market analysts Wireless Intelligence), which is approximately 3 times the number of computers globally. More than a billion cellular connections were added in the past 18 months, with China and India dominating these new connections with approximately 830 million and 706 million users respectively. However, the vast majority of these cellphone connections are currently “low functionality” wireless mobile cellphones and PDAs with only approximately 450 million mobile Internet users in 2009, about 10% of overall users (International Data Corporation cited in PC World http://www.pcworld.com/article/184127/idc—1_billion_mobile_devices_will_go_online_by—2013.html “Worldwide Converged Mobile Device 2009-2013 Forecast Update” December 2009).
However, with the evolution of smartphones, Internet-capable cellphones and PDAs, tablet PCs then as these devices become more affordable these devices will increase, to approximately 1 billion in 2013, being dominated by North America, Europe and Japan, and thereafter increasingly penetrating markets such as China and India. Accordingly, the average user will increasingly consume bandwidth and network resources as well as potentially accessing multiple services simultaneously, for example VoIP and Internet access for streaming multimedia or accessing information. Accordingly, for telecommunication service providers managing congestion as well as access for users is, and increasingly will be, an important issue. This will be further exacerbated as guaranteed network access is required, either to extend existing wired service level agreements (SLAs) for enterprises to wireless networks or where critical applications such as those relating to financial, security or medical applications are executed through the mobile devices.
Generally, wireless telecommunications networks comprise communication stations that transmit and receive wireless communication signals between each other. Depending upon the type of system, these communication stations typically are one of two types of wireless transmit/receive units (WTRUs): one type is the Access Point (AP) or base station, the other is the station (STA) or subscriber unit, which may or may not be mobile.
The term AP as used herein includes, but is not limited to, a base station, an Access Point, Node B, site controller, wireless router or other interfacing device or WTRU in a wireless environment, that provides other WTRUs with wireless access to a network with which the AP is associated. The AP may be associated with wired and/or wireless network(s). The term STA as used herein includes, but is not limited to, a station WTRU, user equipment, a mobile station, fixed or mobile subscriber unit, pager, or any other type of device capable of operating in a wireless environment and accessing an AP to obtain access to the network. Such STAs can include personal communication devices, such as cellular telephones, video phones, so-called Internet ready phones that have network connections. In addition, STAs can include portable personal computing and communication devices, such as smartphone, PDAs, netbook computers/laptop computers/tablet PCs etc. with wireless modems that have similar network capabilities, multimedia players, and gaming consoles. STAs that are portable or can otherwise change location are referred to as mobile units. In some instances, STAs may also provide AP functionality by operating at two telecommunication standards simultaneously.
Typically, a network of APs is provided wherein each AP is capable of conducting concurrent wireless communications with appropriately configured STAs, as well as other multiple appropriately configured APs. Some STAs may alternatively be configured to conduct wireless communications directly between each other, i.e., without being relayed through a network via an AP. This is commonly called peer-to-peer wireless communications. Where a STA is configured to communicate directly with other STAs it may itself also be configured as and function as an AP. STAs can be configured for use in multiple networks, including for example those with both network and peer-to-peer communications capabilities as well as supporting single or multiple basic service sets.
One type of wireless system, called a wireless local area network (WLAN), can be configured to conduct wireless communications with STAs equipped with WLAN modems that are also able to conduct peer-to-peer communications with similarly equipped STAs. It should be noted that in IEEE standards an STA is typically associated as being the WLAN modem rather than a station comprising such a modem. Currently, WLAN modems are being integrated into many traditional communicating and computing devices by manufacturers including, but not limited to, cellular phones, personal digital assistants, and laptop computers. Popular WLAN environments with one or more WLAN APs are generally those constructed according to one or more of the IEEE 802 family of wireless standards. Access to these networks usually requires user authentication procedures. Protocols for such systems exist at multiple levels of maturity including those that have been ratified as standards and are commercially deployed, those that are being formalized for ratification and may or may not be commercially deployed, those that are proposed and are being refined by industry prior to commercial release/ratification, and legacy/obsolete standards. As such IEEE 802 is one such family of standards, and multiple standards are active simultaneously and extensively globally.
A basic service set (BSS) is the basic building block of an IEEE 802.11 WLAN, which comprises WTRU STAs. A set of STAs that can talk to each other can form a BSS. A single-cell wireless LAN using the IEEE 802.11 Wireless LAN Standard therefore is a Basic Service Set (BSS) network. Multiple BSSs are interconnected through an architectural component called a distribution system (DS), to form an extended service set (ESS). An ESS satisfies the need for large coverage networks of arbitrary size and complexity to form the wireless infrastructure that consumers take for granted.
The IEEE 802.11 Wireless LAN Standard is published in multiple parts including:                IEEE 80.211-1997 (802.11 legacy) with spread-spectrum transmission at 1-2 Mb/s at 900 MHz or 2.4 GHz;        IEEE 802.11a-1999 for unlicensed portions of the radio spectrum, usually either in the 2.4 GHz Industrial, Scientific, and Medical (ISM) band or the 5 GHz Unlicensed-National Information Infrastructure (U-NII) band with orthogonal frequency division multiplexing (OFDM) to deliver up to 54 Mb/s data rates;        IEEE 802.11b-1999 designed for the 2.4 GHz ISM band and uses direct sequence spread spectrum (DSSS) to deliver up to 11 Mb/s data rates with reduced range;        IEEE 802.11g-2003 designed for the 2.4 GHz ISM band with OFDM at datarates up to 54 Mb/s;        IEEE 802.11k exposes various measurements to facilitate the management and maintenance of a mobile Wireless LAN;        IEEE Std 802.11-2007 Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications;        IEEE 802.11n which adds multiple-input multiple output (MIMO) antennas, channel bonding etc to support data rates to several 100s Mb/s;        IEEE 802.11r which provide continuous connectivity for wireless devices in motion through fast secure handoffs;        IEEE 802.11s which addresses mesh networks;        IEEE 802.11u that addresses interoperability of IEEE 802.11 devices with external networks; and        IEEE 802.11v that addresses management of STAs.        
The IEEE 802.11 Wireless LAN Standard defines at least two different physical (PHY) specifications and one common medium access control (MAC) specification. Other wireless LAN standards include: IEEE 802.16a (WiMAX), UMTS (Universal Mobile Telecommunication System), EV-DO (Evolution-Data Optimized), CDMA 2000, GPRS (General Packet Radio Service), EDGE (Enhanced Data Rates for GSM Evolution), Open Air (which was the first wireless LAN standard), HomeRF (designed specifically for the home networking market), and HiperLAN1/HiperLAN2 (the European counterpart to the “American” 802.11a standard). Bluetooth is a personal area network (PAN) standard alongside other standards such as ZigBee (including IEEE 802.15), Wireless USB, 6IoWPAN (IPv6 over Low Power Wireless), and UWB (ultra-wideband). PAN standards typically addressing low-power, short-range, wireless connections.
For the purposes of defining aspects of wireless networks and their operating principles the background and embodiments of the invention will be described with respect to the IEEE 802.11 Wireless LAN Standard, which describes two major components, the mobile station (STA) and the fixed access point (AP). It would be understood by one skilled in the art that the embodiments of the invention and the principles within the specification overall may be applied to other wireless networks, including but not limited to those operating to standards such as those defined supra.
IEEE 802.11 networks can also have an independent configuration where the mobile stations communicate directly with one another, without support from a fixed AP. The medium access control (MAC) protocol regulates access to the RF physical link in such independent configurations and provides basic access mechanisms with clear channel assessment, channel synchronization, and collision avoidance using the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) access method. The MAC also provides link setup, data fragmentation, authentication, synchronization, encryption, and power management.
Synchronization is the process of STAs in an IEEE 802.11 wireless LAN cell getting in step with each other, so that reliable communication is possible. The MAC also provides the basis for synchronization mechanisms that allow for some physical layers to make use of frequency hopping or other time-based mechanisms wherein the parameters of the physical layer change with time. This process involves an AP sending a beacon frame to announce the presence of a wireless LAN cell or a STA inquiring to find a wireless LAN cell. Once a wireless LAN cell is found, a STA joins the wireless LAN cell in a process managed by the distributed wireless LAN cells.
In an independent BSS (IBSS) wireless LAN cell, there is no access point (AP) to act as the central time source for the wireless LAN cell. In such an IBSS a wireless LAN cell timer synchronization is distributed among the mobile STAs of the IBSS wireless LAN cell. Since there is no AP, the mobile STA that starts the IBSS wireless LAN cell will begin by resetting its TSF timer to zero and transmitting a beacon frame. This establishes the basic beaconing process for this IBSS wireless LAN cell after which each STA will attempt to send a beacon after the target beacon transmission time (TBTT) arrives. To minimize actual collisions of the transmitted beacon frames on the medium, each STA in the wireless LAN cell will choose a random delay value, which it will allow to expire before it attempts its beacon transmission.
In order for a STA to communicate with other STAs in a wireless LAN cell, it must first find the AP. The process of finding another STA is by inquiry, which may be either passive or active. Passive inquiry involves only listening for IEEE 802.11 traffic whereas active inquiry requires the inquiring STA to transmit and invoke responses from IEEE 802.11 APs and allows an IEEE 802.11 STA to find a wireless LAN cell while minimizing the time spent inquiring. Once all responses are received, or the STA has decided there will be no responses, it may change to another channel and repeat the process. At the conclusion of this the STA has accumulated information about the wireless LAN cells in its vicinity. To join the selected wireless LAN cell all of the STA's MAC and physical parameters must be synchronized with the desired wireless LAN cell. Once this is complete, the STA has joined the wireless LAN cell and is ready to begin communicating.
Each STA and AP in an IEEE 802.11 wireless LAN implements the MAC layer service, which provides the capability for STAs to exchange MAC frames. The MAC layer transmits management, control, or data frames between STAs and APs, which once formed is passed to the Physical Layer for transmission. But before transmitting a frame, the MAC layer must first gain access to the network. Three interframe space (IFS) intervals defer an IEEE 802.11 STA's access to the medium and thus provide one mechanism of establishing priority, but for the STA and not its traffic. Each IFS defines the duration between the end of the last symbol of the previous frame to the beginning of the first symbol of the next frame. The Short Interframe Space (SIFS) provides the highest priority level by allowing some frames to access the medium before others.
The Priority Interframe Space (PIFS) is used for high priority access to the medium during the contention-free period. A point coordinator in the AP connected to the backbone network controls the priority-based Point Coordination Function (PCF) to dictate which STAs in a cell can gain access to the medium by sending a contention-free poll frame to a STA, thereby granting the STA permission to transmit a single frame to any destination.
The Distributed Coordination Function (DCF) Interframe Space (DIFS) is used for transmitting low priority data frames during the contention-based period. The DIFS spacing delays the transmission of lower priority frames to occur later than the priority-based transmission frames.
During the contention-based period, the DCF uses the Carrier-Sense Multiple Access with Collision Avoidance (CSMA/CA) contention-based protocol, which is similar to IEEE 802.3 Ethernet. This CSMA/CA protocol minimizes the chance of collisions between STAs sharing the medium by utilizing a random back-off interval to delay transmission by a STA.
Within the IEEE 802.11 Standard, the channel is shared by a centralized access protocol, the Point Coordination Function (PCF), to provide contention-free transfer based on a polling scheme controlled by the AP of a BSS. This feature, however, is typically not exploited in commercial systems. The centralized access protocol gains control of the channel and maintains control for the entire contention-free period by waiting the shorter Priority Interframe Space (PIFS) interval between transmissions than the STAs using the Distributed Coordination Function (DCF) access procedure. Following the end of the contention-free period, the DCF access procedure begins, with each STA contending for access using the CSMA/CA method. The 802.11 MAC Layer thereby provides both contention and contention-free access to the shared wireless medium through the use of various MAC frame types to implement the required functions of MAC management, control, and data transmission.
Quality of service (QoS) is a measure of service quality provided to a customer, using the STA. The primary measures of QoS are message loss, message delay, message jitter, and network availability. Voice and video applications have the most rigorous QoS requirements. Interactive data applications such as Web browsing have lower delay and loss requirements, but they are sensitive to errors. Non-Real Time applications such as file transfer, email, and data backup operate acceptably across a wide range of loss rates and delay. Prioritized packet scheduling, packet dropping, and bandwidth allocation are among techniques available, within the prior art, at the various nodes of the network, including APs, that enable packets from different applications to be treated differently, thereby helping to achieve different QoS objectives. Many network providers guarantee specific QoS and capacity levels through the use of Service-Level Agreements (SLAs). An SLA is a contract between an enterprise user and a network provider that specifies the capacity (and possibly other performance measures) to be provided between points in the network that must be delivered with a specified QoS. If the network provider fails to meet the terms of the SLA, then the user may be entitled to some form of compensation. The SLA is typically offered by network providers for private line, frame relay, ATM, or Internet networks employed by enterprises and generally only for wired services due to issues including, but not limited to, access, contention, data rates that have been discussed above as well as others such as handover between APs during roaming, for example, that are discussed below.
The problem of overlapping AP coverage is acute when wireless LANs are installed without any awareness of what other wireless LANs are operating nearby. Consequently, multiple-cell wireless LANs typically rely on a medium access control (MAC) protocol to allocate channel time among STAs in order to avoid co-channel interference between APs, just as it avoids contention among STAs within the same cell associated with an AP.
Additional MAC protocols are provided for wireless LANs because transmission may be flawed by higher bit error rates and different losses that are experienced on a wireless channel depending on the path on which the signal travels. Additive noise, path loss and multipath interference result in more retransmissions and necessitate additional acknowledgements, as successful transmission cannot be taken for granted, all of which further reduce the actual bandwidth available to the traffic the STA is trying to send or receive. These effects, amongst others such as physical barriers, can also result in what are known as “hidden” STAs wherein an STA is visible to an AP but not from other STAs communicating with the AP. Accordingly, these STAs that cannot hear or be heard by a source STA are capable of causing interference to the destination STA of a transmission. Generally, a message exchange mechanism known in the art as Request-to-Send/Clear-to-Send (RTS/CTS) alleviates the hidden terminal problem. RTS/CTS may also provide a reservation mechanism that can save bandwidth in wireless LANs. The inability to detect a collision as quickly as it can be detected on cable with carrier-sense multiple access with collision detection (CSMA/CD) causes more channel time to be wasted in a collision while waiting for the entire frame to transmit before the collision is detected. Hence, carrier sensing is combined with the RTS/CTS mechanism to give carrier-sense multiple access with collision avoidance (CSMA/CA).
To address enhancements to the MAC protocols for achieving acceptable QoS for WLANs IEEE 802.11e-2005 (IEEE 802.11e) was formalized as an approved amendment to the IEEE 802.11 standard by providing modifications to the MAC. The standard is considered of critical importance for delay-sensitive applications, such as Voice over Wireless LAN and streaming multimedia, and has subsequently been incorporated into the IEEE 802.11-2007 standard. IEEE 801.11e provides for enhanced DCF (EDCF) and enhanced PCF (EPCF) through a new coordination function, the hybrid coordination function (HCF). IEEE 801.11e also includes additional Admission Control in that the AP publishes available bandwidth in beacons such that STAs can check the available bandwidth before adding more traffic.
The EDCF mechanism employs the Tiered Contention Multiple Access (TCMA) protocol that has basic access rules that similar to CSMA but now transmission deferral and backoff countdown depend on the priority classification of the data. A STA still waits for an idle time interval before attempting transmission following a busy period, but the length of this interval is no longer equal to DIFS but equal to the Arbitration-Time Inter-Frame Space (AIFS), which varies with the priority of the data. Equally, for high priority data contention window (CW) duration is reduced such that the random back-offs are shorter. Additionally, IEEE 802.11e provides contention-free access to the channel for a period called a Transmit Opportunity (TXOP), which is a bounded time interval during which a STA can send as many frames as possible. Accordingly, higher priority data gets to the channel faster. Additionally, countdown of the backoff timer in an STA does not commence when a busy period completes unless the channel has been idle for a period. This causes the backoff countdown of lower priority data frames to slow down and even freeze if there are higher-priority frames ready to transmit. This slow down/freezing is a common occurrence in situations of congestion thereby limiting transmission of data frames that have a priority below that of those seizing and holding the channel. The Wi-Fi Alliance (a trade association that promotes wireless LAN technology) certifies products if they conform to interoperability standards, such as Wireless Multimedia Extensions (WME) (also known as Wi-Fi Multimedia (WMM)) which is based on the IEEE 802.11e standard. WMM certified APs must be enabled for EDCA and TXOP whilst all other IEEE 802.11e enhancements are optional.
The EPCF maintains multiple traffic queues at the STAs for different traffic categories with higher-priority frames being scheduled for transmission first. Delays are reduced through improved polling-list management, which maintains only active STAs on it. A STA with data to transmit must reserve a spot on that list, where it stays as long as it is active and for a limited number of inactive polling cycles. As such IEEE 802.11e provides a generalization of PCF in that it allows for contention-free transfers to occur as needed; not necessarily at pre-determined regular repeat times. An AP can thus send (and possibly receive) data to STAs in its BSS on a contention-free basis. This contention-free session, referred to as a contention-free burst (CFB), helps an AP transmit its traffic, which is typically heavier in infrastructure cells (since STAs must communicate exclusively through the AP).
Attention must also been given to the problem of co-channel overlapping BSSs (OBSSs), particularly with dense deployments. Channel re-use in multiple-cell Wireless LANs, which is necessary due to the small number of channels in the unlicensed band, three non over lapping channels for IEEE 802.11b/g (24 for IEEE 802.11a), can lead to a high degree of overlap in the coverage areas of co-channel WLAN cells. This overlap is exacerbated by the typically ad hoc placement of WLANs. This also potentially poses a problem for the PCF and HCF, as contention-free sessions (CFSs) are generated without coordination among co-channel APs when contention free periods are enabled. The existing standards do not provide adequate coordination for contention-free sessions in such situations.
Within OBSSs channel access time (or bandwidth) should also be allocated among the multiple co-channel cells in order to avoid interference. To be efficient, a channel should not remain idle if there is data waiting for transmission and as channel selection within the IEEE 802.11 standard is fixed or static, then bandwidth allocation should be dynamic so that an STA only gets the bandwidth it needs, thereby increasing efficiency. Potentially, this bandwidth allocation may change on a per-transmission basis if something occurs to impact the path, for example distance from AP increasing or barrier interference. Beneficially, dynamic bandwidth allocation promotes fair access to the channel for all co-channel cells. The success rate of a STA in accessing its assigned channel either by its AP generating CFSs or by (E)DCF transmissions, should be independent of its location, assuming comparable traffic loads. Without a mechanism to manage access under high traffic loads transmissions can be delayed excessively in the disadvantaged cell(s), such that important STAs/sessions do not get the bandwidth they require such that they fail to meet QoS requirements.
Not surprisingly, within the prior art there are multiple disclosures of techniques and methods for controlling access to Wi-Fi networks as well as providing QoS, managing congestion, taking APs offline etc that seek to either address the limitations within the IEEE 802.11 standards or extend upon them. A subset of these prior art approaches are discussed below in respect of FIGS. 1 through 7. Amongst these techniques are:
Management of Beacon Power, wherein an AP uses beacon frames for example to announce the presence of a wireless LAN cell, transmit timing information and the length of the contention-free interval. Adjustments to the beacon power form the basis of solutions taught in US Patent Application 2008-0,112,326 “Load Balancing Routes in Multi-Hop Ad-Hoc Wireless Networks”, U.S. Pat. No. 7,715,353 “Wireless LAN Cell Breathing”, US Patent Application 2007-0,248,033 “Methods and Devices for Balancing the Load of Access Points in Wireless Local Area Networks”, and US Patent Application 2007-0,248,059 “Wireless LAN Cell Breathing.”
Management of Beacon Timing, see for example U.S. Pat. No. 7,222,175 “Dynamically Configurable Beacon Intervals for Wireless LAN Access Points.”
Received Signal Strength Indicator (RSSI) and QoS Indicators at STA, see for example U.S. Pat. No. 7,065,063 “System and Method for Balancing Communication Traffic Between Adjacent Base Stations in a Mobile Communications Network”, US Patent Application 2009-0,310,569 “System and Method for Balancing Communication Traffic Between Adjacent Base Stations in a Mobile Communications Network”, U.S. Pat. No. 7,200,395 “Wireless Station Protocol Apparatus”, U.S. Pat. No. 7,158,787 “Wireless Station Protocol Method”, U.S. Pat. No. 7,206,297 “Method for Associating Access Points with Station using Bid Techniques”, U.S. Pat. No. 7,248,574 “Apparatus for Selecting an Optimum Access Point in a Wireless Network”, U.S. Pat. No. 7,274,930 “Distance Determination Program for use by Devices in a Wireless Network”, U.S. Pat. No. 7,307,976 “Program for Selecting an Optimum Access Point in a Wireless Network on a Common Channel”, and US Patent Application 2004-0,166,867 “Program for Ascertaining a Dynamic Attribute of a System.”
AP Loading Determination, see for example US Patent Application 2008-0,316,985 “WLAN having Load Balancing Based on Access Point Loading”, U.S. Pat. No. 7,400,901 “WLAN having Load Balancing Based on Access Point Loading”, U.S. Pat. No. 7,366,103 “Seamless Roaming Options in an IEEE 802.11 Compliant Network”, U.S. Pat. No. 7,362,776 “Method for Multicast Load Balancing in Wireless LANs”, US Patent Application 2004-0,120,290 “Admission Control in a Wireless Communication Network”, and US Patent Application 2008-0,151,807 “Method for Multicast Load Balancing in Wireless LANs.”
QoS Signaling, see for example US Patent Application 2008-0,101,231 “Wi-Fi Quality of Service Signaling.”
Managing STA Attributes and Configuration, see US Patent Application 2006-0,165,031 “Apparatus and Method for Delivery handling Broadcast and Multicast Traffic as Unicast Traffic in a Wireless Network”, U.S. Pat. No. 7,146,166 “Transmission Channel Selection Program”, U.S. Pat. No. 7,307,972 “Apparatus for Selecting an Optimum Access Point in a Wireless Network on a Common Channel”, U.S. Pat. No. 7,369,858 “Apparatus for Self-Adjusting Power at a Wireless Station to Reduce Inter-Channel Interference”, US Patent 2004-0,192,279 “Program for Scanning Radio Frequency Channels” “WLAN having Load Balancing Based on Access Point Loading”, and US Patent Application 2008-0,151,807 “Method for Multicast Load Balancing in Wireless LANs.”
Global Release, predominantly for reacquisition although also for removing an AP temporarily or permanently. See for example U.S. Pat. No. 7,280,517 “Wireless LANs and Neighborhood Capture”, US Patent Application 2003-0,086,437 “Overcoming Neighborhood Capture in Wireless LANs”, US Patent Application 2008-0,019,343 “Wireless LANs and Neighborhood Capture”, and U.S. Pat. No. 7,647,046 “Maintaining Uninterrupted Service in a Wireless Access Point and Client Stations Thereof.”
AP Directed Transfer to another AP, see for example US Patent Application 2006-0058056 “Method for Controlling Handoff between Secondary Agents in a Wireless Communications System”, U.S. Pat. No. 7,706,326 “Wireless Communications Methods and Components that Implement Handoff in Wireless Local Area Network”, and US Patent Application 2004-0,264,394 “Method and Apparatus for Multi-Channel Wireless LAN Architecture.”
Higher Level Protocols wherein APs are directed, see for example US Patent Application 2007-0,286,202 “Methods and Systems for Call Admission Control and Providing Quality of Service in Broadband Wireless Access Packet-Based Networks”, U.S. Pat. No. 7,826,426 “Seamless Mobility in Wireless Networks”, and US Patent Application 2004-0,202,130 “Apparatus for Associating Access Points with Stations in a Wireless Network.”
AP Characteristics and Configuration, see for example U.S. Pat. No. 7,274,945 “Transmission Channel Selection Apparatus”, U.S. Pat. No. 7,366,537 “Wireless Network Apparatus and System”, US 2004-0,166,870 “Distributed Protocol for use in a Wireless Network”, and US Patent Application 2004-0,203,688 “Apparatus for Adjusting Channel Interference between Access Points in a Wireless Network.”
Polling STAs, see for example 2008-0,013,522 “Wireless LANs and Neighborhood Capture”, and US Patent Application 2006-0,072,488 “Point-Controlled Contention Arbitration in Multiple Access Wireless LANs”, US Patent Application 2005-01,070,263 “Wireless Access Point Protocol Logic”, and US Patent Application 2004-0,202,122 “Wireless Access Point Protocol Program”
Overall the 802.11 protocol is designed to provide equal opportunity for all STAs to seize the RF channel. However, with different classes-of-service, a STA transmitting Real Time traffic should receive priority in seizing the RF channel to improve delay, jitter and loss to these services over other traffic either from the same STA or from other STAs. Whilst the IEEE standard 802.11e provides a mechanism to achieve this prioritization it requires that both the APs and the STAs support this protocol. Critically IEEE 802.11e requires that key elements be applied to the STAs, which as discussed supra are in the majority of cases consumer devices that only provides basic IEEE 802.11 functionality without QoS or other features. Advanced features such as QoS (IEEE 802.11e) and Signaling for Load Distribution are not expected to be ubiquitously deployed and available anytime soon for several factors including, but not limited to
1. some of these standards are yet not ratified and hence the standardized functions are not available in Wi-Fi chip sets;
2. modification to applications running on STAs would be required to interwork with the QoS and traffic management functions that are deployed in the chip sets; and
3. many legacy STAs will continue to operate even when standards are deployed so a QoS solution is still needed for these legacy STAs.
Consequently, ubiquitous penetration of such QoS compliant STAs to the more general consumer base in markets for many years. In 2009 the top 5 manufacturers sold 888 million devices from a total sales base of 1 billion units. Even at these high rates, which are driven by the current massive subscriber increases in China and India, and hence likely to drop as market penetration reaches 100% of the world's population, it would take nearly 6 years to replace all existing handsets in the consumer's hands with QoS compliant STAs.
Recently, significant attention has been focused on smartphones as opposed to feature phones, together with their operating systems such as Android (Google), Apple iOS and Symbian. Smartphones typically allow the user to install and run more advanced applications as they run a complete operating system whereas feature phones have less advanced programming and are typically based on Java ME or BREW. Yet in both Q3 and Q4 2010 (July-September) when compared to 2009 sales were still dominated by feature phones and in fact low cost feature phones increased market share. Overall smartphones currently account for only 20% of handset shipments, and typically most consumers today exploit only voice and data services like the majority of consumers with their feature phones.
Equally today, in 2011, Wi-Fi enabled devices typically sold often do not support IEEE 802.11e. Those that do however, such as laptop computers and netbooks, generally do not use it due to the nature of the applications they run. Accordingly, it would be beneficial to provide a method today that provides for enhancing QoS, provides resilient connectivity, and increases useable network capacity and bandwidth to users of Wi-Fi networks when using Real Time services such as voice (VoIP), video and interactive data, as well data services such as email, FTP, web browsing, etc on basic Wi-Fi devices that do not support QoS features.
Providing resilient connectivity between each STA and AP means that each STA sees a good RF signal with good Signal to Noise and Interference Ratio (SNIR). Increasing useable network capacity and bandwidth means that each STA can transmit and receive packets using maximum over-the-air data rate and that over-the-air congestion is controlled and minimized. Enhancing service quality means ensuring that delay, loss and jitter are managed to a level where Real Time services perform, for example voice quality obtains a Mean Opinion Score (MOS) of 3.8 or higher (where MOS tests for voice are established by ITU-T recommendation P.800).
Whilst standards are evolving to address some of these issues, however, standards development, ratification and industry adoption are moving slowly. In other areas devices supporting QoS today, such as netbooks and laptops, are either not mass consumer market products or are not supported by the application. It would thereby be beneficial to provide a network-based solution sooner that supports legacy STAs as well as new QoS compliant STAs and additionally augments standards based QoS-compliant APs.